oracle 触发器实现主键自增

drop table book;

--创建表

create table book(

   bookId varchar2(4) primary key,

   name varchar2(20)

);

--创建序列

create sequence book_seq start with 1 increment by 1;

--创建触发器

create or replace trigger book_trigger

before insert on book

for each row

begin

select book_seq.nextval into :new.bookId from dual;

end ;

--添加数据

insert into book(name)  values (‘cc‘);

insert into book(name)  values (‘dd‘);
commit;
查询数据：select * from book; 

查询
select * from user_objects ubs where ubs.OBJECT_TYPE=‘SEQUENCE‘; 

oracle 触发器实现主键自增